Crystal oscillator drive circuit, controller, air conditioning control system and variable frequency air conditioner

Abstract

This application relates to the field of air conditioning technology and provides a crystal oscillator drive circuit, controller, air conditioning control system, and variable-frequency air conditioner. The crystal oscillator drive circuit includes a power supply, a peripheral application circuit, and a GM self-feedback regulation circuit. The power supply generates a reference current that is output to an amplifier in the peripheral application circuit. The GM self-feedback regulation circuit generates an additional compensation current that varies with the crystal oscillation amplitude, compensating the reference current and driving the amplifier. This application can self-regulate the amplifier GM until the crystal oscillator starts to oscillate stably under various conditions, thereby achieving excellent reliability and a very wide range of applicability.

Description

Technical Field

[0001] The present application relates to the technical field of variable frequency air conditioners, and in particular to a crystal oscillator drive circuit, a controller, an air conditioning control system, and a variable frequency air conditioner. Background Art

[0002] As the heartbeat of a chip, the accuracy and reliability of the clock directly impact its reliability and performance. Crystal oscillators, with their superior accuracy and longevity, have long been the primary source of clocks for chips.

[0003] However, as the industry develops, the application scope of chips is becoming increasingly broad, and the requirements for their extreme operating conditions are becoming increasingly stringent. It is very difficult to ensure the reliability of traditional crystal oscillator circuits under conditions such as extreme voltage, extreme temperature, and extreme humidity.

[0004] The existing technology uses INV as an amplifier to drive an external crystal oscillator. A current source with a constant drive capability is used to power INV, and an OTA and a reference are used to monitor the amplitude of the crystal oscillator in real time, ultimately achieving both driving the external oscillator and limiting the amplitude. However, structures like the above are limited by application conditions. The transconductance gm of the amplifier INV comes from the MOS devices that make up INV. MOS devices have consistency deviations during the manufacturing process, and gm also has large offsets under extreme temperature application conditions. Therefore, under extreme application conditions, the crystal oscillator is prone to stopping. Summary of the Invention

[0005] The main purpose of this application is to overcome the problem that the crystal oscillator in the above-mentioned prior art is prone to stop oscillating, and to provide a crystal oscillator drive circuit, controller, air conditioning control system and variable frequency air conditioner that can improve the reliability of the crystal oscillator circuit.

[0006] According to one aspect of the present application, a crystal oscillator drive circuit is provided, including a power supply, a peripheral application circuit, and a GM self-feedback regulation circuit; the power supply generates a reference current output to an amplifier of the peripheral application circuit, and the GM self-feedback regulation circuit generates an additional compensation current that varies with the crystal oscillation amplitude, and drives the amplifier after compensating the reference current.

[0007] Optionally, the gm self-feedback regulation circuit includes a coupling capacitor, a fourth MOS transistor, a filter circuit, a current mirror circuit, and a voltage bias circuit;

[0008] The feedback capacitor is connected to a crystal oscillator, and the oscillating AC signal of the crystal oscillator is transmitted to the gate of the fourth MOS transistor through the filter circuit and the voltage bias circuit. The gate voltage of the fourth MOS transistor changes with the oscillation amplitude, and the output current of the gm self-feedback regulation circuit is regulated through self-regulation of the current mirror circuit.

[0009] Optionally, the current mirror circuit includes a first MOS transistor, a second MOS transistor and a third MOS transistor; the current output ends of the first MOS transistor and the second MOS transistor are connected to the current input end of the third MOS transistor, the first MOS transistor is connected to the drain of the fourth MOS transistor, and the source of the third MOS transistor is connected to the peripheral application circuit.

[0010] Optionally, the mirror ratio of the first MOS transistor, the second MOS transistor, and the third MOS transistor is 1:1:1, and the ratio of currents flowing through the first MOS transistor, the second MOS transistor, and the third MOS transistor is 1:1:1.

[0011] Optionally, the filtering circuit includes a first resistor and a capacitor; one end of the first resistor is connected to the gate of the fourth MOS tube and the capacitor respectively, and the other end is connected to the coupling capacitor, for filtering and accumulating the AC voltage signal connected to the coupling capacitor.

[0012] Optionally, the voltage bias circuit includes a second resistor and a fifth MOS tube; one end of the second resistor is connected to the gate of the fifth MOS tube, and the other end is connected to the current mirror circuit to form a voltage self-bias, which is used to hinder and weaken the influence of the AC voltage signal connected to the coupling capacitor; one end of the resistor is also connected to the filter circuit, which is used to connect the DC voltage of the fifth MOS tube to the fourth MOS tube to provide a DC voltage bias.

[0013] Optionally, the output current of the power supply is I0, where I0=IREF; the output current of the gm self-feedback regulation circuit is I1, where I1=k / R 2 , k=2 / (β*W / L)*(1-1 / √K) 2 ; Wherein, β is a process parameter, W and L are design parameters of the fourth MOS tube and the fifth MOS tube respectively, and K is the ratio of the number of the fourth MOS tube to the number of the fifth MOS tube.

[0014] Optionally, the driving current on the amplifier is I D , I D =I1+IREF.

[0015] Optionally, the transconductance of the amplifier is gm;

[0016] in,

[0017] Optionally, the peripheral application circuit further includes a reference current source module, the current output end of the power supply is connected to the current input end of the reference current source module, and the current output end of the reference current source module is connected to the amplifier drain.

[0018] Optionally, the crystal oscillator driving circuit further includes a clock translation circuit, which is connected to the amplifier drain and outputs the signal of the amplifier drain.

[0019] According to another aspect of the present application, a controller adopts the above-mentioned crystal oscillator driving circuit.

[0020] According to another aspect of the present application, an air-conditioning control system includes the above-mentioned controller.

[0021] According to another aspect of the present application, a variable frequency air conditioner includes the above-mentioned air conditioning control system.

[0022] As can be seen from the above technical solutions, the advantages and positive effects of the crystal oscillator drive circuit, controller, air conditioning control system and variable frequency air conditioner of the present application are:

[0023] The present application provides a crystal oscillator driving circuit, which uses a peripheral application circuit combined with a gm self-feedback adjustment circuit to adjust the transconductance gm of the amplifier until the crystal oscillator starts oscillating smoothly, thereby greatly improving the reliability of the crystal oscillator circuit.

[0024] The beneficial effects of a controller provided in this application are consistent with those of the above-mentioned control valve core, which will not be described in detail here.

[0025] The present application provides an air conditioning control system, the beneficial effects of which are consistent with those of the above-mentioned controller and will not be described in detail here.

[0026] The present application provides a variable frequency air conditioner, the beneficial effects of which are consistent with those of the above-mentioned air conditioning control system, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 is a first circuit diagram of a crystal oscillator driving circuit according to an exemplary embodiment;

[0030] Figure 2 is a second circuit diagram of a crystal oscillator driving circuit according to an exemplary embodiment;

[0031] Figure 3A third circuit diagram of a crystal oscillator driving circuit is shown according to an exemplary embodiment.

[0032] The description of the accompanying drawings is as follows:

[0033] 100. Peripheral application circuit; 200. GM self-feedback regulation circuit; 210. Filter circuit; 220. Current mirror circuit; 230. Voltage bias circuit; 300. Clock translation circuit; 4. Reference current source module; 5. Crystal oscillator. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] See also Figure 1-Figure 3 , Figure 1 is a first circuit diagram of a crystal oscillator driving circuit according to an exemplary embodiment; Figure 2 is a second circuit diagram of a crystal oscillator driving circuit according to an exemplary embodiment; Figure 3 A third circuit diagram of a crystal oscillator driving circuit is shown according to an exemplary embodiment.

[0036] The existing technology uses INV as an amplifier to drive an external crystal oscillator. A current source with a constant drive capability is used to power INV, and an OTA and a reference are used to monitor the amplitude of the crystal oscillator in real time, ultimately achieving both driving the external oscillator and limiting the amplitude. However, structures like the above are limited by application conditions. The transconductance gm of the amplifier INV comes from the MOS devices that make up INV. MOS devices have consistency deviations during the manufacturing process, and gm also has large offsets under extreme temperature application conditions. Therefore, under extreme application conditions, the crystal oscillator is prone to stopping.

[0037] In order to solve the above technical problems, the present application provides a crystal oscillator drive circuit. Figure 3 , Figure 1-Figure 3 A crystal oscillator driving circuit that can embody the principles of the present application is representatively shown, including a power supply Vcc, a peripheral application circuit 100, and a gm self-feedback regulation circuit 200; the power supply generates a reference current and outputs it to the amplifier M0 of the peripheral application circuit 100, and the gm self-feedback regulation circuit 200 generates an additional compensation current that varies with the crystal oscillation amplitude, and drives the amplifier M0 after compensating the reference current.

[0038] Here, this application utilizes a peripheral application circuit 100 combined with a GM self-feedback adjustment circuit 200 to adjust the amplifier's transconductance GM until the crystal oscillator 5 successfully starts oscillating, significantly improving the reliability of the crystal oscillator 5 circuit. Compared to other traditional crystal oscillator circuits, this application offers the following economic benefits: products utilizing this technology can simultaneously meet a variety of complex and extreme application environments, significantly enhancing product versatility. GM adaptive technology enables the circuit to be applied in a wide range of extreme operating conditions, from extremely low to extremely high temperatures, significantly improving product versatility and reliability.

[0039] Optionally, the gm self-feedback regulation circuit 200 includes a coupling capacitor Cc, a fourth MOS transistor M4, a filter circuit 210, a current mirror circuit 220, and a voltage bias circuit 230; the feedback capacitor Cc is connected to the crystal oscillator 5, and the oscillating AC signal of the crystal oscillator 5 is transmitted to the gate of the fourth MOS transistor M4 through the filter circuit 210 and the voltage bias circuit 230. The gate voltage of the fourth MOS transistor M4 changes with the oscillation amplitude, and the output current of the gm self-feedback regulation circuit 200 is regulated through self-regulation of the current mirror circuit 220.

[0040] The current mirror circuit 220 includes a first MOS transistor M1, a second MOS transistor M2, and a third MOS transistor M3. The current output terminals of the first MOS transistor M1 and the second MOS transistor M2 are connected to the current input terminal of the third MOS transistor M3. The first MOS transistor M1 is connected to the drain of the fourth MOS transistor M4. The source of the third MOS transistor M3 is connected to the peripheral application circuit 100.

[0041] Specifically, the mirror ratio of the first MOS transistor M1 , the second MOS transistor M2 , and the third MOS transistor M3 is 1:1:1, and the ratio of the current flowing through the first MOS transistor M1 , the second MOS transistor M2 , and the third MOS transistor M3 is 1:1:1.

[0042] In addition, the filter circuit 210 includes a first resistor R1 and a capacitor C0; one end of the first resistor R1 is connected to the gate of the fourth MOS transistor M4 and the capacitor C0 respectively, and the other end is connected to the coupling capacitor Cc. The coupling capacitor Cc is connected to the gate of the amplifier M0 and is used to filter and accumulate the AC voltage signal connected to the coupling capacitor Cc.

[0043] On this basis, the voltage bias circuit 230 includes a second resistor R2 and a fifth MOS transistor M5. One end of the second resistor R2 is connected to the gate of the fifth MOS transistor M5, and the other end is connected to the current mirror circuit 220 to form a voltage self-bias, which is used to reduce the influence of the AC voltage signal connected to the coupling capacitor Cc. One end of the second resistor R2 is also connected to the filter circuit 210, which is used to pass the DC voltage of the fifth MOS transistor M5 to the fourth MOS transistor M4 to provide a DC voltage bias.

[0044] Specifically, if the gm self-feedback regulation circuit 200 short-circuits the gate and source of the fifth MOS tube, the performance of the gm self-feedback regulation circuit 200 will deteriorate significantly and the regulation effect will be greatly weakened. By optimizing the performance of the gm self-feedback regulation circuit 200 through the second resistor R2, the regulation effect will be greatly enhanced.

[0045] For the completeness of the solution, the source of the fourth MOS transistor M4 is grounded through a resistor R to prevent excessive current, and the source of the fifth MOS transistor M5 and the capacitor C0 are both grounded.

[0046] like Figure 2 The output current I0 of the reference current source module 4 is:

[0047] I0=IREF

[0048] To save power, IREF is typically set at a few hundred nanoamperes. However, under extreme application conditions, currents of several hundred nanoamperes are highly susceptible to noise interference and, in high temperature and high humidity conditions, can even be overwhelmed by leakage current. Therefore, it's easy to see that crystal oscillator circuits driven solely by IREF are unreliable and lack robustness.

[0049] In this embodiment, the gm self-feedback regulating circuit 200 of the present application is as follows: Figure 3 As shown in the reference "Design of Analog CMOS and Integrated Circuits" Behzad Razavi ISBN: 0-07-238032-2 Section 11.2, the output current I1 is:

[0050] I1=k / R 2

[0051] Where k is a parameter that has nothing to do with temperature and power supply Vcc (related to design and process),

[0052] k=2 / (β*W / L)*(1-1 / √K) 2 ;

[0053] Wherein, β is a process parameter, and K is the ratio of the number of the fourth MOS transistor M4 to the number of the fifth MOS transistor M5.

[0054] In CMOS technology, all MOS devices have two design parameters: Width (abbreviated as W, channel width) and Length (abbreviated as L, channel length). The ratio of W to L (i.e., W / L) is proportional to the MOS device's overcurrent capability. The MOS device's overcurrent capability is given by the following formula:

[0055]

[0056] Process parameters are inherent parameters determined by the manufacturing process and are unrelated to the circuit in this application. These parameters vary depending on the specific manufacturing process characteristics and have a very wide range. For example, the current mainstream chip manufacturing process is silicon-based, so some inherent parameters of silicon (such as band gap magnitude and thermal voltage) determine the basic characteristics and laws (such as turn-on threshold and carrier mobility) of the basic unit of the manufactured circuit—MOS transistor.

[0057] The above formula represents the output current of the gm self-feedback regulation circuit 200 when the crystal oscillator 5 is not oscillating, that is, when no AC signal passes through the capacitor Cc.

[0058] By adjusting the design parameters, I1 is generally designed to be a few microamperes to more than ten microamperes.

[0059] At this time, the driving circuit I on the amplifier M0 D have:

[0060] I D =I1+IREF

[0061] Right now

[0062] I D =2 / (β*W / L) / R 2 *(1-1 / √K) 2 +IREF

[0063] It can be seen that at this time I D Much larger than IREF.

[0064] The transconductance gm of amplifier M0 is:

[0065]

[0066] gm represents the transconductance of M0, which is determined by the drain current I D The gate-source voltage V GS The derivative is:

[0067]

[0068] The MOS tube drain current I D By its gate-source voltage V GS Decide:

[0069]

[0070] Derivative of this formula is:

[0071]

[0072] Then, by combining this formula with the previous formula, we can get:

[0073]

[0074] Among them, μC OX is the process parameter, namely the β mentioned above, W and L are the design parameters of M0, V GS is the gate-source voltage of M0, V TH is the opening threshold of M0, I D is the drain current of M0.

[0075] When the AC voltage signal input via coupling capacitor Cc has a small amplitude (in the initial oscillation phase) or no AC voltage (not yet oscillated), first resistor R1 and capacitor C0 form a simple filter circuit 210 to filter out the AC voltage, thereby unaffecting the Gate voltage of fourth MOS transistor M4. The current flowing through first MOS transistor M1 also flows through fourth MOS transistor M4. The output current I1 of third MOS transistor M3 depends on the current flowing through first MOS transistor M1. Therefore, it is easy to see that the output current I1 of third MOS transistor M3 is unaffected at this time. As can be seen from the gm formula above, gm is maximum at this time, the oscillation conditions are most relaxed, and crystal oscillator 5 easily starts oscillating.

[0076] When the AC voltage signal input via coupling capacitor Cc exceeds a certain amplitude (the specific parameters are determined by the values ​​of first resistor R1 and capacitor C0), the simple filter circuit 210 formed by first resistor R1 and capacitor C0 cannot completely filter out the signal. This affects the gate voltage of the fourth MOS transistor M4, causing it to gradually decrease. This reduces the current flowing through the fourth MOS transistor M4. Similarly, it is easy to see that the output current I1 of the third MOS transistor M3 also gradually decreases. Based on the gm formula above, it can be seen that gm also gradually decreases at this time, the oscillation starting conditions become increasingly stringent, and the amplitude of the crystal oscillator 5 is gradually limited and reduced. Consequently, the amplitude of the AC voltage signal input via coupling capacitor Cc decreases simultaneously, while the gate voltage of the fourth MOS transistor M4 increases, and the current flowing through the fourth MOS transistor M4 increases. Ultimately, the self-regulating circuit reaches equilibrium, and the amplitude of the crystal oscillator 5 stabilizes at a certain amplitude.

[0077] Similarly, if the oscillation amplitude of the crystal oscillator 5 decreases or even stops oscillating due to deterioration of application conditions (e.g., a significant drop in temperature or an increase in humidity), the oscillating AC signal is transmitted to the gate of the fourth MOS transistor M4 via the feedback capacitor Cc. After filtering by the first resistor R1 and the capacitor C0, the gate voltage of the fourth MOS transistor M4 increases as the oscillation amplitude of the crystal oscillator 5 decreases. Consequently, through self-regulation of the circuit, the current I0 output to the amplifier M0 increases (due to the increase in I1). Consequently, the transconductance gm of the amplifier M0 of the crystal oscillator 5 also increases synchronously, ultimately increasing the oscillation amplitude of the crystal oscillator 5 until it stabilizes.

[0078] In summary, the crystal oscillator circuit with gm self-feedback adjustment circuit 200, during actual circuit operation, will detect the oscillation amplitude of the crystal oscillator 5 in real time, and then adjust the transconductance gm of the amplifier M0 in real time based on changes in operating conditions, ensuring reliable operation of the crystal oscillator circuit temperature. This achieves the purpose of adaptive operation.

[0079] In this embodiment, Figure 1-Figure 2 As shown, the peripheral application circuit 100 includes an amplifier M0, a feedback resistor R0, a crystal oscillator 5, a first capacitor C1 and a second capacitor C2; the gate of the amplifier M0 is connected to one end of the crystal oscillator 5 and the input end of the gm self-feedback regulation circuit 200, the drain of the amplifier M0 is connected to the other end of the crystal oscillator 5, the output end of the gm self-feedback regulation circuit 200 and the output end of the power supply Vcc, and the source of the amplifier M0 is grounded; the two ends of the feedback resistor R0 are respectively connected to the two ends of the crystal oscillator 5; the upper plate of the first capacitor C1 and the upper plate of the second capacitor C2 are respectively connected to the two ends of the crystal oscillator 5, and the lower plate of the first capacitor C1 and the lower plate of the second capacitor C2 are both grounded.

[0080] Among them, the function of amplifier M0 is to receive the voltage signal at one end of crystal oscillator 5 (gate), amplify it, and output it to the other end of crystal oscillator 5 (drain), so as to promote the continuous oscillation of crystal oscillator 5. The function of feedback resistor R0 is to provide DC bias for amplifier M0, maintain the operating point, and thus enable amplifier M0 to operate normally. The function of first capacitor C1 and second capacitor C2 is to store energy for crystal oscillator 5, ensuring that a certain amount of energy exchange is maintained at both ends of crystal oscillator 5 to offset the energy loss caused by irrational factors of components during the oscillation process, so that the oscillation can continue stably.

[0081] Furthermore, the peripheral application circuit 100 further includes a reference current source module 4 , the current output terminal of the power supply Vcc is connected to the current input terminal of the reference current source module 4 , and the current output terminal of the reference current source module 4 is connected to the drain of the amplifier M0 .

[0082] In addition, the crystal oscillator driving circuit further includes a clock translation circuit 300 . The clock translation circuit 300 is connected to the drain of the amplifier M0 and outputs the signal from the drain of the amplifier M0 .

[0083] As can be seen from the above, the reference current source module 4 generates a reference current output to drive amplifier M0. The gm self-feedback regulation circuit 200 generates an additional compensation current that varies with the crystal oscillation amplitude. This current compensates the reference current and drives amplifier M0. The clock translation circuit 300 is connected to the drain of amplifier M0 and translates the sinusoidal oscillation signal into a square wave clock signal with a specific duty cycle for output.

[0084] This embodiment also provides a controller that adopts the above-mentioned crystal oscillator driving circuit.

[0085] This embodiment also provides an air conditioning control system, which adopts the above-mentioned controller.

[0086] This embodiment also provides a variable frequency air conditioner, which adopts the above air conditioning control system.

[0087] It should be pointed out that the above-mentioned controller, air conditioning control system and variable frequency air conditioner are all based on the crystal oscillator drive circuit, and therefore have all the advantages of the crystal oscillator drive circuit, which will not be elaborated here.

[0088] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0089] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A crystal oscillator driving circuit, characterized in that: It includes a power supply, a peripheral application circuit (100) and a gm self-feedback regulation circuit (200); The power supply generates a reference current which is output to the amplifier of the peripheral application circuit (100); the gm self-feedback regulating circuit (200) generates an additional compensation current which varies with the crystal oscillation amplitude, and drives the amplifier after compensating the reference current; The gm self-feedback regulating circuit (200) comprises a coupling capacitor, a fourth MOS transistor, a filter circuit (210), a current mirror circuit (220), and a voltage bias circuit (230); The feedback capacitor is connected to a crystal oscillator (5); the oscillating AC signal of the crystal oscillator (5) is transmitted to the gate of the fourth MOS transistor through the filter circuit (210) and the voltage bias circuit (230); the gate voltage of the fourth MOS transistor changes with the oscillation amplitude, and the output current of the gm self-feedback regulation circuit (200) is regulated through self-regulation of the current mirror circuit (220).

2. A crystal oscillator driving circuit according to claim 1, characterized in that: The current mirror circuit (220) comprises a first MOS transistor, a second MOS transistor and a third MOS transistor; The current output terminals of the first MOS tube and the second MOS tube are connected to the current input terminal of the third MOS tube, the first MOS tube is connected to the drain of the fourth MOS tube, and the source of the third MOS tube is connected to the peripheral application circuit (100).

3. A crystal oscillator driving circuit as claimed in claim 2, characterized in that: The mirror ratio of the first MOS transistor, the second MOS transistor and the third MOS transistor is 1:1:1, and the ratio of currents flowing through the first MOS transistor, the second MOS transistor and the third MOS transistor is 1:1:

1.

4. A crystal oscillator driving circuit as claimed in claim 2, characterized in that: The filtering circuit (210) includes a first resistor and a capacitor; One end of the first resistor is connected to the gate of the fourth MOS tube and the capacitor respectively, and the other end is connected to the coupling capacitor, and is used to filter and accumulate the AC voltage signal connected to the coupling capacitor.

5. The crystal oscillator driving circuit according to claim 1, wherein: The voltage bias circuit (230) includes a second resistor and a fifth MOS tube; One end of the second resistor is connected to the gate of the fifth MOS tube, and the other end is connected to the current mirror circuit (220) to form a voltage self-bias, which is used to prevent and weaken the influence of the AC voltage signal connected to the coupling capacitor; One end of the second resistor is also connected to the filter circuit (210) and is used to connect the DC voltage of the fifth MOS transistor to the fourth MOS transistor to provide a DC voltage bias.

6. A crystal oscillator driving circuit as claimed in claim 5, characterized in that: The output current of the power supply is I0, I0=IREF; The output current of the gm self-feedback regulating circuit (200) is I1, I1=k / R 2 , k=2 / (β*W / L)*(1-1 / √K) 2 ; Wherein, β is a process parameter, W and L are design parameters of the fourth MOS transistor and the fifth MOS transistor, and K is the ratio of the number of the fourth MOS transistor to the number of the fifth MOS transistor.

7. A crystal oscillator driving circuit as claimed in claim 6, characterized in that: The current of the driving circuit on the amplifier is I D , I D =I1+IREF.

8. A crystal oscillator driving circuit as claimed in claim 7, characterized in that: The transconductance of the amplifier is gm; in, 9. The crystal oscillator driving circuit according to claim 1, wherein: The peripheral application circuit (100) further comprises a reference current source module (4), the current output end of the power supply is connected to the current input end of the reference current source module (4), and the current output end of the reference current source module (4) is connected to the amplifier drain.

10. The crystal oscillator driving circuit according to claim 1, wherein: The crystal oscillator driving circuit further comprises a clock translation circuit (300), wherein the clock translation circuit (300) is connected to the amplifier drain and outputs a signal from the amplifier drain.

11. A controller, characterized in that: A crystal oscillator drive circuit as described in any one of claims 1 to 10 is used.

12. An air conditioning control system, characterized in that: Comprising the controller of claim 11.

13. A variable frequency air conditioner, characterized in that: It includes the air conditioning control system as claimed in claim 12.

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